二氧化氯氧化硫代硫酸钠的pH动力学分析  

pH KINETICS ANALYSIS ON THE OXIDATION OF THIOSULFATE BY CHLORINE DIOXIDE

作　　者：曹向禹[1] 黄君礼[1] 崔崇威[1] 

机构地区：[1]哈尔滨工业大学市政环境工程学院

出　　处：《环境化学》2007年第3期357-361,共5页Environmental Chemistry

基　　金：国家自然科学基金资助项目(50178022)

摘　　要：在pH值大于9和温度为25.0±0.01℃条件下,采用pH值探针技术研究二氧化氯氧化硫代硫酸钠反应体系在封闭搅拌状态下的动力学行为,结果表明,在封闭条件下体系的pH值呈现比较复杂的准振荡现象,大致经过四个阶段(Ⅰ,Ⅱ,Ⅲ,Ⅳ)的下降:(Ⅰ)下降来源于二氧化氯的自身歧化反应动力学;(Ⅱ)下降来源于连四硫酸钠的水解反应动力学;(Ⅲ)下降来源于硫代硫酸钠被二氧化氯氧化的主反应动力学;(Ⅳ)下降来源于ClO2-和ClO2与连四硫酸钠及其水解产物的反应动力学.其中,连四硫酸钠的碱性水解反应是pH值动力学的关键.The kinetics of the chlorine dioxide-thiosulfate reaction in an unbuffered basic solution had been investigated in a stirred tank reactor at 25.0±0.01℃ with pH probe, and a 12-step mechanism model about the system is suggested to describe the observed behavior of the system. The experimental results indicate that the reaction between chlorine dioxide and thiosulfate exhibits a rich variety of pH oligo-oscillatory phenomena in a batch, in which the four sequential stage drop in pH （Ⅰ,Ⅱ,Ⅲ,Ⅳ） were obtained approximately： （Ⅰ）the initial very slow drop in pH is originated from the disproportionate reaction of chlorine dioxide; （Ⅱ） a very smooth decrease in pH for some time come from the alkaline hydrolysis reaction of tetrathionate; （Ⅲ） a abrupt pH drop is formed as the main reaction of the oxidation thiosulfate by chlorine dioxide ; （Ⅳ） the following reaction between chlorite or chlorine dioxide and tetrathionate along with its hydrolysis products such as sulfite accounts for the fourth slow drop in pH. The alkaline hydrolysis reaction of tetrathionate plays a significant role in the pH kinetics of chlorine dioxide-thiosulfate at pH 〉 9.

关 键 词：二氧化氯 硫代硫酸钠 动力学 

分 类 号：X132[环境科学与工程—环境科学]